Abstract:

To achieve optimal mechanical properties of konjac glucomannan (KGM) film prepared by the solution casting method, Plackett-Burman factorial design was used to select the most important ones affecting KGM film tensile strength out of 7 technological parameters and subsequently, the optimal values of selected parameters, namely KGM concentration (X1), stirring time (X2), heating temperature (X3), standing time (X5) and drying temperature (X7), for improved KGM film tensile strength were investigated using response surface analysis based on a 5-variable, 3-level central composite design leading to 46 experiments. Results showed that the above selected parameters all had significant effects on KGM film tensile strength in the decreasing order: X1 ＞ X3 ＞ X2 ＞ X7 ＞ X5 and their optimal values were as follows: KGM concentration 2.19 g/100 mL, heating temperature 60.0 ℃ for 190 min stirring, standing time 156 min and drying temperature 51.1 ℃. The KGM film obtained under such conditions exhibited a smooth regular surface, an optimal tensile strength and good water resistance.

Key words: konjac glucomannan, tensile strength, response surface analysis